The present invention relates to a fastening device and further relates to a fastening device for a prosthesis, the fastening device having a cylindrical channel and inclined washer designed to accept insertion of a cylindrical insert, such as a tube, bar or peg, with minimal resistance and yet substantially prevent withdrawal of the cylindrical insert from the fastening device unless a release mechanism is operated to permit withdrawal. In addition, the present invention relates to a fastening device which permits rotation of the cylindrical insert with respect to the fastening device while still securely fastening the cylindrical insert within the fastening device, so as to prevent unlocking of the device and separation of the cylindrical insert.
The present invention has been developed especially in order to be used as a fastening device for prostheses, for example artificial legs, to a prosthesis sleeve which is attached to an amputated leg, but it may also be used in many other connections where a device with the corresponding quality and function is desired. The problems, which are solved by the invention connected with the fastening device for prostheses, are to obtain a safe fastening and simple detaching without tools. Moreover, the fastening device has to allow a certain turning movement and lock steplessly without backlash against moving apart when loaded and with compression between prosthesis and prosthesis sleeve. These and other problems are solved with a fastening device according to the invention, comprising a house with an inclined washer, which can be turned and is kept inclined by a spring in a way which appears clearly from the special part of the description, and a cylindrical part, for instance in the form of a peg on the part which the part with the fastening device is to be connected to.
It is known to use inclined, elastic or spring loaded thin metal elements with holes slightly bigger than the tube or rod which is locked in one direction by the metal element. These are used for example as jacks, door closers, etc. In these cases the metal element and the tube or rod are often mutually guided in such a way that no relative turning can be done. Because this would generally mean that the locking action of the inclined metal element will come to an end. Therefore, before the some about of the present invention it has not been possible to use this simple locking principle in those cases where a secure locking has been necessary also in combination with a possibility of relative turning and detaching of the metal element with its locking function from the tube or rod.